Yield predictions based on Drew and Flewelling's (1979) Density Management Diagram for coastal Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, were compared with remeasured plot data from British Columbia. The diagram overestimated standing volume by 64% and mean diameter by 24%, on average. Volumes predicted for plantations established at initial densities between 300 and 3000 trees per hectare exceeded nearly all the plots in the data base. Because of the unattainable production targets set by the diagram, strategic plans based on its predictions would be seriously in error. Consequently, the diagram cannot be used in its current form as a silvicultural planning tool in stands of Douglas-fir on the coast of British Columbia.
FRDA Research Report 024 (1399 KB)
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Updated July 24, 2015